_**Update:** With the advent of Go 1.11 and [Go modules][1], this whole post is now useless. Unset your GOPATH entirely and switch to Go modules today!_
Maybe someday I’ll start writing about things besides Go again.
Go requires that you set an environment variable for your workspace called your `GOPATH`. The `GOPATH` is one of the most confusing aspects of Go to newcomers and even relatively seasoned developers alike. It’s not immediately clear what would be better, but finding a good `GOPATH` value has implications for your source code repository layout, how many separate projects you have on your computer, how default project installation instructions work (via `go get`), and even how you interoperate with other projects and libraries.
It’s taken until Go 1.8 to decide to [set a default][2] and that small change was one of [the most talked about code reviews][3] for the 1.8 release cycle.
After [writing about GOPATH himself][4], [Dave Cheney][5] [asked me][6] to write a blog post about what I do.
### My proposal
I set my `GOPATH` to always be the current working directory, unless a parent directory is clearly the `GOPATH`.
Here’s the relevant part of my `.bashrc`:
```
# bash command to output calculated GOPATH.
calc_gopath() {
local dir="$PWD"
# we're going to walk up from the current directory to the root
while true; do
# if there's a '.gopath' file, use its contents as the GOPATH relative to
# the directory containing it.
if [ -f "$dir/.gopath" ]; then
( cd "$dir";
# allow us to squash this behavior for cases we want to use vgo
if [ "$(cat .gopath)" != "" ]; then
cd "$(cat .gopath)";
echo "$PWD";
fi; )
return
fi
# if there's a 'src' directory, the parent of that directory is now the
# GOPATH
if [ -d "$dir/src" ]; then
echo "$dir"
return
fi
# we can't go further, so bail. we'll make the original PWD the GOPATH.
if [ "$dir" == "/" ]; then
echo "$PWD"
return
fi
# now we'll consider the parent directory
dir="$(dirname "$dir")"
done
}
my_prompt_command() {
export GOPATH="$(calc_gopath)"
# you can have other neat things in here. I also set my PS1 based on git
# state
}
case "$TERM" in
xterm*|rxvt*)
# Bash provides an environment variable called PROMPT_COMMAND. The contents
# of this variable are executed as a regular Bash command just before Bash
# displays a prompt. Let's only set it if we're in some kind of graphical
# terminal I guess.
PROMPT_COMMAND=my_prompt_command
;;
*)
;;
esac
```
The benefits are fantastic. If you want to quickly `go get` something and not have it clutter up your workspace, you can do something like:
```
cd $(mktemp -d) && go get github.com/the/thing
```
On the other hand, if you’re jumping between multiple projects (whether or not they have the full workspace checked in or are just library packages), the `GOPATH` is set accurately.
More flexibly, if you have a tree where some parent directory is outside of the `GOPATH` but you want to set the `GOPATH` anyways, you can create a `.gopath` file and it will automatically set your `GOPATH` correctly any time your shell is inside that directory.
The whole thing is super nice. I kinda can’t imagine doing something else anymore.
